The use of biomaterials as restorative materials, in both the dental and medical fields is growing and the requirements for such materials are often times difficult to achieve. Restorative materials such as amalgam or resin composites are often used to repair dental tissues and bones.
For example, there has been considerable research devoted to the improvement of the adhesion of resins to hard tissues such as dentin or enamel. The adhesives are typically applied to the hard tissue after a pretreatment or etch of the tissue with an acidic solution. Various resin composites are available and generally suffer one or more disadvantages in providing a satisfactory bond between the tissue and the restorative material. Some of adhesive materials are designed to achieve higher bond strengths between tissue layers or the treated tissue and a restorative material, to improve physical properties, or the esthetics of the restored target substrate. Other desired properties of such adhesive composites are directed to their use and include ease in preparation and formulation for use under relatively humid conditions.
Typically an etch solution is utilized to remove the smear layer and demineralize the surface of the dental tissue. The etch solution can alter wettability or chemical reactivity of the pretreated dentin, prior to applying a bonding adhesive agent which is generally a polymerizable monomer. Polymerization of the bonding agent facilitates the bonding agent to adhere to the dentin. The interaction(s) between the bonding agent and the treated substrate is not entirely understood and is believed to be related to chemical, mechanical, interfacial diffusion or a combination of all three physical processes. Polymerization of most bonding adhesives provide an approximately 5-micron thick hybrid layer that is formed of part resin and part dentin. The depth and effectiveness of the penetration of the bonding agent is an important and often critical aspect to the adhesion between the bonding agent and substrate. This hybrid layer is believed to contain little or no apatite and the adhesion to dentin is believed to occur through collagen with the bonding agent.
Even though there has been continued research in the area of etching solutions and bonding agents, the techniques and/or products currently available for pretreating the dental or bone tissue or adhering a restorative material to the bone or dental tissue have limitations. For example, the bonding agents should effectively seal the dentin tubules to prevent postoperative sensitivity and protect the pulp. Additionally, the bonds should last the lifetime of the restorative correction and be durable under a variety of conditions.
Therefore, a need exists for new compositions, solutions and methods that overcome one or more of the disadvantages of currently available products.